1. Field of the Invention
This invention relates to a tensioning device, and more particularly to a sand belt-tensioning device that includes a drive roller and a resilient member for tautening a sand belt on the drive roller.
2. Description of the Related Art
Referring to FIG. 1, a conventional grinding device is shown to include a drive roller 1 and a sand belt 2 wound around the drive roller 1. The drive roller 1 has a roller body 11, and two opposite end surfaces that are formed respectively and integrally with two aligned rotating shafts 12. Two fixing members 13 are sleeved respectively and fixedly on the first and second rotating shafts 12, abut respectively against the end surfaces of the drive roller 1, and are connected respectively and fixedly to two opposite ends of the sand belt 2.
Referring to FIG. 2, during use of the conventional grinding device, the roller 1 is rotated, and a wooden workpiece 3 is pressed against a bottom side of the roller 1. The wooden workpiece 3 is also moved in a horizontal direction in such a manner that frictional contact therebetween is maintained. Therefore, a top surface of the wooden workpiece 3 is finished. During movement of the wooden workpiece 3 under the grinding device, a portion 23 of the sand belt 2 is pushed by the wooden workpiece 3 to move away from an outer surface of the roller 1. This results in unsmooth movement of the wooden workpiece 3 and a dissatisfactory grinding effect.